Foraging patterns in the Antarctic Shag Phalacrocorax bransfieldensis at Harmony Point, Antarctica

CASAUX R.; BERTOLIN M.

Workshop; The CCAMLR Ecosystem Monitoring and Management Working Group; 2018

Abstract. During the 1995 and 1996 summer seasons the foraging patterns of theAntarctic Shag Phalacrocoraxbransfieldensis were studied by direct observation on individuals breedingat Harmony Point, Nelson Island, South Shetland Islands. During pre-laying andincubation individuals of both sexes usually foraged once a day, females earlyin the morning and males when their partners returned to their nests. Comparedto those periods, when rearing chicks parents incremented the number of dailyforaging trips, usually alternating the time at sea, and reduced their duration.Rearing individuals responded to increasing energy requirements at the nests(i.e. as chicks grew older or at increasing number of chicks at the nests) byincrementing the number of daily foraging trips and the daily time invested inforaging activities. The information obtained suggests that Antarctic shagsinvest time in activities which lead them buffer variable food abundance orenergy requirements at the nests. The possibility of using the foragingparameters considered in this study in ecosystem monitoring programmes isdiscussed.